There is known a device capable of communicating with an external apparatus by using the technology of so-called energy harvesting that generates electric power on the basis of energy present in a surrounding environment, such as solar power generation and vibration power generation.
For example, Patent Literature 1 discloses a power generation device including a power generation unit that generates electric power on the basis of energy present in a surrounding environment. This power generation device has a communication function and is configured to be capable of transmitting power generation information to a host apparatus.
Meanwhile, since electric power generated by energy harvesting is minute, the technology that efficiently uses the minute electric power is anticipated.
For example, Patent Literature 2 discloses a power storage circuit including a first capacitance connected to an input terminal to which a minute current is input, an electric-field detection type switch whose on/off is controlled in accordance with a power storage voltage of the first capacitance, a second capacitance connected to the electric-field detection type switch, and an electronic circuit switch whose on/off is controlled in accordance with a power storage voltage of the second capacitance.